Cents-per-km vs Logbook: Which Saves More?
Australia is unique among the four jurisdictions TruMile supports in offering two genuinely different methods that produce very different deductions for very different drivers. Picking the wrong one costs real money.
When cents-per-km wins
Drivers under 5,000 business km per year: cents-per-km is simpler, requires no receipts, and produces the same or larger deduction as logbook for low-cost vehicles.
Drivers with newer, fuel-efficient cars and modest annual driving: the 88-cent rate often exceeds actual per-km costs once you factor in low-fuel-burn engines and minimal maintenance.
When the logbook method wins
Drivers exceeding 5,000 business km per year: cents-per-km is hard-capped at $4,400 per car. Logbook has no cap.
Drivers with expensive vehicles (high insurance, high depreciation, high finance costs): actual per-km costs can exceed 88 cents quickly. A $60,000 ute with 6,000 business km could deduct $7,000+ via logbook versus the $4,400 cents-per-km maximum.
Drivers with old, paid-off cars but high maintenance and insurance: cents-per-km includes a depreciation component that a fully depreciated vehicle does not benefit from. Logbook lets you claim actual costs without the wasted depreciation portion.
Worked example: 8,000 km/year
Cents-per-km: $4,400 (capped at 5,000 km × $0.88).
Logbook (assuming 80% business use, $12,000 annual costs): $9,600. Logbook wins by $5,200.
Worked example: 3,000 km/year
Cents-per-km: $2,640 ($0.88 × 3,000).
Logbook (assuming 60% business use, $8,000 annual costs): $4,800. Logbook still wins, but the gap is smaller and the simplicity of cents-per-km may be worth the difference.
FAQ
Can I use cents-per-km for one car and logbook for another?
Yes. Each car is independent. You can run the simpler method on a low-mileage second car and logbook on a high-mileage primary work vehicle.
What's the simplest decision rule?
If your business driving is under 5,000 km and your car is reasonably new and inexpensive, use cents-per-km. If your business driving exceeds 5,000 km or your car has high actual costs, run the logbook math; it usually wins. If unsure, do both calculations once and pick the larger.
Track your Australia business mileage.
Free for 40 auto trips a month. ATO rates handled with the right tier and cap.
Download free on the App Store